Electric Heating Systems and Associated Methods

ABSTRACT

Electric heating systems and associated methods for central heating and/or space heating that circulate a heating medium (e.g., antifreeze) and may comprise a tank, a pump, a motor blower, and a heater core. In certain applications, the tank may be an un-insulated rectangular tank that is fabricated from a material comprising black iron.

BACKGROUND

The present disclosure generally relates to electric heating systems. In particular, in one or more embodiments, the present disclosure relates to electric heating systems and associated methods for central heating and/or space heating that circulate a heating medium (e.g., antifreeze) and may comprise a tank, a pump, a motor blower, and a heater core.

A variety of different heating systems have been used heretofore for both central heating and space heating. In a typical central heating system, the system generates heat at a single location and then distributes that heat to the interior of a building. Such systems may be used in private homes, public buildings, and commercial buildings. Central heating systems may be combined with other systems that provide ventilation and air conditioning to a building. These combined heating, ventilating, and air conditioning systems are commonly referred to by the acronym “HVAC.” Fossil fuels, electricity, solar energy, and heat pumps may be used to provide the heat needed in a central heating system. This heat may be distributed through the house by heating a fluid (e.g., air, steam, water) that is circulated through the building. By way of example, a duct system may be used to distribute heated air through a building. By way of further example, pipes may be used to distribute heated water/steam through a building to radiators that transfer the heat from the heated water/steam to the building's air. Drawbacks to these conventional heating systems may include energy consumption, as well as environmental hazards, such as potentially undesirable levels of oxygen consumption.

Thus, there is a need for improved heating systems that can be used for central heating and/or space heating.

SUMMARY

An embodiment of the present invention provides an electric heating system. The electric heating system may comprise a tank for storing a heating medium. The electric heating system further may comprise an electric heating element disposed in the tank for heating the heating medium in the tank. The electric heating system further may comprise a pump for circulating the heating medium in the electric heating system. The electric heating system further may comprise a heater core in fluid connection with the tank for exchanging heat between the heating medium and air. The electric heating system further may comprise a motor blower for forcing the air across the heater core.

Another embodiment of the present invention provides an electric heating system. The electric heating system may comprise an un-insulated rectangular tank that comprises a heating medium and that is constructed from a material comprising black iron. The heating medium may comprise antifreeze. The electric heating system further may comprise an electric heating element disposed in the tank for heating the heating medium in the tank. The electric heating system further may comprise a circulating pump for circulating the heating medium in the electric heating system. The electric heating system further may comprise a heater core in fluid connection with the tank for exchanging heat between the heating medium and air. The electric heating system further may comprise a motor blower for forcing the air across the heater core and having an air intake. The air intake for the motor blower may be located a distance of about ½ inch to about 1 inch from a side of the tank.

Another embodiment of the present invention provides a heating method. The heating method may comprise heating a liquid in a tank with an electric heating element. The heating method further may comprise directing the liquid from the tank to a heater core. The heating method further may comprise forcing air across the heater core with a motor blower, whereby heat is exchanged from the liquid to the air. The method further may comprise returning the liquid from the heater core to the tank.

The features and advantages of the present invention will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustrating the various components of an electric heating system in accordance with one embodiment of the present invention.

FIG. 2 is a schematic illustrating the various components of an electric heating system in accordance with one embodiment of the present invention.

FIG. 3 is a schematic illustrating a tank and its various components in accordance with one embodiment of the present invention.

FIG. 4 is a schematic illustrating the relationship between the blower and the tank in accordance with one embodiment of the present invention.

FIG. 5 is a schematic illustrating incorporation of a heater core into a duct system in accordance with one embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure generally relates to electric heating systems. In particular, in one or more embodiments, the present disclosure relates to electric heating systems and associated methods for central heating and/or space heating that circulate a heating medium (e.g., antifreeze) and may comprise a tank, a pump, a motor blower, and a heater core. In accordance with embodiments of the present invention, the electric heating system may be used for central heating, space heating, or any other suitable heating purpose. For example, the electric heating system may used in a central heating system to provide heat for a private home, public building, or commercial building. By way of further example, the electric heating system may be used locally to provide heat to a space, such as a room, warehouse, or the like.

There may be several potential advantages to the systems and methods of the present invention, only some of which may be alluded to herein. One of the many potential advantages of the systems and methods of the present invention is that the embodiments of the electric heating systems of the present invention may utilize less energy than conventional heating systems, whether the conventional systems rely on electricity, heating oil, propane, or the like to provide energy. For example, embodiments of the present invention may utilize up to six times less energy than a conventional electric heater. Another potential advantage of the systems and methods of the present invention may be reduced environmental hazards, in that embodiments of the present invention may consume less (or potentially no) oxygen when compared to conventional heating systems. Yet another potential advantage may be that embodiments of the present invention may have reduced risk of fire as compared to heating systems, for example, that rely on fossil fuels for energy.

FIGS. 1 and 2 illustrate an electric heating system 10 in accordance with one embodiment of the present invention. FIG. 2 is a top schematic view illustrating the general arrangement of the various components of the electric heating system 10. As illustrated, the electric heating system 10 may include tank 20 for storing a heating medium, pump 30 for circulating the heating medium, heater core 40 for exchanging heat between the heating medium and air, and motor blower 50 for forcing air across the heater core 40. Cover 60 may also be provided for enclosing the system 10. In the illustrated embodiment, the heating medium (e.g., antifreeze) may be heated to a desired temperature in the tank 20. A heating medium feed 70 may carry the heating medium from the tank 20 to the heater core 40 by way of the pump 30. A heating medium return 80 may then carry the heating medium back to the tank 20. In the heater core 40, heat may be transferred from the heating medium to the air that may be forced across the heater core 40 by the motor blower 50. The heated air may then be distributed as desired for a particular application. In certain embodiments, a duct system may be used to distribute the heated air through a home or building, such as when the system 10 is used for central heating.

Referring now to FIG. 3, the tank 20 is illustrated in more detail in accordance with one embodiment of the present invention. As illustrated, the tank 20 may include a heating medium return 80 and a heating medium outlet 90. The heating medium may be drawn from the tank 20 via the heating medium outlet 90 and returned to the tank 20, after circulation through the heater core 40, via the heating medium return 80. In certain embodiments, the tank 20 may be raised a short distance from the base of the cover 60. Additionally, in certain embodiments, the tank 20 may not be insulated such that heat is lost from the tank 20. At least a portion of the heat lost from the tank 20 may be recovered by the motor blower 50, thus increasing the efficiency of the motor blower 50. By way of example, passive heat loss from the tank 20 may heat surrounding air that is then drawn into the motor blower 50. In this manner, the motor blower 50 intakes air that is hotter than ambient room temperature. In addition, passive heat loss from the tank 20 may also serve as a space heater, heating the room in which the system 10 is located.

Any of a variety of suitable materials may be used to construct the tank 20. Examples of suitable metals include black iron, cast iron, and aluminum. Black iron generally refers to a type of metal constructed from steel that is not galvanized. Black iron tanks may be preferred in certain applications due to their improved heat absorption, for example, as compared with galvanized metals. Improved heat absorption may be preferred, in certain embodiments, to provide increased passive heat loss from the tank 20. Passive heat loss from the tank 20 may be captured, for example, in air that is drawn into the motor blower 50 and/or in a metal strap (as discussed below) that may connect the tank 20 and the motor blower 50. In accordance with embodiments of the present invention, the tank 20 may constructed from a material comprising black iron and having a thickness of about ⅛ inch.

The tank 20 may be of any general shape, including, for example, rectangular, square, cylindrical, oval, and a variety of other shapes that may be suitable for a particular application. In certain embodiments, the tank 20 may be a horizontal rectangular tank. Rectangular tanks may be desired in certain applications due to their case of construction, cost, and passive heat loss, as compared to cylindrical tanks. As mentioned above, passive heat loss from the tank 20 may be desired in certain applications. The tank 20 generally should be sized based a number of factors, including the volume of the heating medium needed to provide the desired heat generation. In one particular embodiment, the tank 20 may be about 15 inches in length, about 8 inches in width, and about 14 inches in height.

A heating medium for circulation in the electric heating system 10 may be stored in the tank 20. As illustrated by FIGS. 1 and 2, the heating medium may be circulated in the system 10 in a closed loop in accordance with one embodiment of the present invention. As will be discussed in more detail below, a heating element 100 may be located in the tank 20 for heating the heating medium to a desired temperature. A wide variety of liquids may be suitable for use as the heating medium. Examples of suitable liquids include water, antifreeze, cooking oil, and motor oil. Combinations of suitable liquids may also be suitable. By way of example, one suitable heating medium includes a mixture of water and antifreeze. Ethylene glycol based antifreeze and propylene glycol based antifreeze should both be suitable for use in embodiments of the present invention. To reduce and/or eliminate loss of the heating medium due to evaporation, organic liquids (e.g., antifreeze) may be used in certain embodiments. Additionally, to reduce the risk of fire, antifreeze and/or water may be used in certain embodiments.

As illustrated by FIG. 3, the tank 20 may include a heating element 100, a temperature sensor 110, a thermostat 120, and a relief valve 130. As illustrated, the heating element 100 may be disposed through a side of the tank 20. By way of example, the heating element 100 may be disposed through a nipple that is welded in the side of the tank 20. The heating element 100, in certain embodiments, may be located about 5 inches from the bottom of the tank 20. In certain embodiments, the heating element 100 may be an electric immersion heater. In addition, the heating element 100 may deliver about 2,000 watts of heating output while using about 16.5 amps of power, in accordance with embodiments of the present invention. The heating element 100 may be used, for example, to heat the heating medium to a desired temperature. By way of example, the heating element 100 may heat the heating medium to a temperature of about 120° F. to about 150° F. If the heating element 100 is disconnected from the electricity, the heating medium may remain warm (e.g., above room temperature) for up to about 12 hours, for example. However, the heating element 100 generally should remain connected to an electrical outlet, in accordance with embodiments of the present invention. The tank 20 further may include a temperature sensor 110. The temperature sensor 110, for example, may also be disposed through the side of the tank 20. By way of example, the temperature sensor 110 may be disposed through a nipple that is welded in the side of the tank 20. As illustrated, the temperature sensor 110 may be located above the heating element 100. In certain embodiments, the heating element 100 may have an integrated temperature sensor.

The temperature of the heating medium in the tank 20 may be controlled, in certain embodiments, by the thermostat 120. In certain embodiments, the thermostat 120 may be a digital thermostat. The thermostat 120 may have, for example, a breaker. The thermostat 120 may be set to maintain the temperature of the heating medium at a desired temperature. In this manner, the thermostat 120 may turn off the heating element 100 when the heating medium in the tank 20 reaches or exceeds the desired temperature. For example, the thermostat 120 may turn off the heating element 100 when the temperature of the heating medium reaches about 150° F. Controlling the temperature of the heating medium in the tank 20 is a safety measure that can be used to prevent overheating in the tank 20. As illustrated, the heating element 100 and the temperature sensor 110 may be coupled to the thermostat 120. In the illustrated embodiment, the thermostat 120 is coupled to the side of the tank 20. However, while the thermostat 120 is illustrated on the side of the tank 20, it should be understood that the thermostat 120 may be placed in any suitable location for controlling the temperature of the heating medium.

The relief valve 130 may be disposed in the top of the tank 20, in accordance with embodiments of the present invention. The relief valve 130 generally may serve as an additional safety feature for the electric heating system 10. While the thermostat 120 should control the temperature inside the tank 20, in certain embodiments, the relief valve 130 may be a temperature relief valve, opening to relieve excessive temperature that may be built up inside the tank 20. If there is any exhaust heat from the relief valve 130, this heat should remain within system 10 such that no heat loss occurs, maintaining the system's efficiency. Alternatively, the relief valve 130 may be a pressure relief valve 130, opening to relieve excessive pressure that may be built up inside the tank 20. In certain embodiments, the relief valve 130 may be a temperature/pressure relief valve. The temperature/pressure relief valve may be set to relieve excessive temperature and/or pressure inside the tank 20 if it approaches the limits of the tank 20. The relief valve 130 does not need to be permanently welded to the tank 20. By way of example, the relief valve 130 may be screwed into a nipple that is welded in the top of the tank 20. When needed, the relief valve 130 may be unscrewed for adding and/or replacing the heating medium in the tank 20, for example, during system maintenance.

Referring again to FIGS. 1 and 2, the pump 30 may circulate the heating medium in the electric heating system 10 in accordance with one embodiment of the present invention. As illustrated, the pump 30 draws the heating medium from the tank 20 and delivers it to the heater core 40 by way of the heating medium feed 70. The pump 30 may carry the heating medium from a lower level of the tank 20 to the higher level of the heater core 40. The pump 30 may be connected to the tank 20 via any suitable connection. By way of example, the pump 30 may be connected to the tank 20 by a ⅝ inch heater hose. In certain embodiments, the pump 30 may be modified to have threaded inlet and outlet connections. For example, the pump 30 may be threaded to fit a ⅜ inch adapter for the heater hose. A variety of different circulating pumps may be suitable for use in the electric heating system 10, in accordance with embodiments of the present invention. An example of a suitable circulating pump is Dayton Circulating Pump SM-303-BS, available from W. W. Grainger, Inc. The pump 30 may be rated to withstand the temperatures of the circulating heating medium. For example, the pump 30 may have a maximum temperature of 230° F. or greater.

As illustrated by FIGS. 1 and 2, electric heating system 10 further may include heater core 40. In accordance with embodiments of the present invention, the heater core 40 may be any suitable heat exchanger for exchanging heat from the heating medium with air from blower 50. In certain embodiments, the heater core 40 may be a tube-fin heat exchanger. In these embodiments, the heating medium may be passed through the tubes of the tube-fin heat exchanger while the motor blower 50 forces air across the tubes. The heater core 40 may comprise a number of different suitable materials, including, for example, copper. Heating medium feed 70 may provide the heating medium to the heater core 40. The heating medium may be returned to the tank 20 by heating medium return 80. Any of a variety of different connections may be suitable for connecting the heater core 40 to the pump 30 and the tank 20. In certain embodiments, a ⅝-inch nipple on the heater core 40 may be connected to the heating medium return 80, which may be a ⅝-inch heater hose. A ⅜-inch nipple on the heater core 40 may connect the heater core 40 to the heating medium feed 70 from the pump 30. While not illustrated, the heater core 40 may be covered, for example, by a square metal cover, for example, in embodiments where the system 10 is portable. As previously mentioned, the electric heating system 10 may be portable for a number of applications, including space heating. Alternatively, the heater core 40 may be connected to a duct. The heater core 40 may be connected to a duct for a number of applications, including central heating. By way of example, the heater core 40 may be connected in a duct of an HVAC system.

FIG. 4 illustrates the motor blower 50, in accordance with one embodiment of the present invention. As previously mentioned, the motor blower 50 may force air across the heater core 40 such that heat from the heating medium is transferred to the air. This heated air may then be used for central or space heating, for example. As illustrated, the motor blower 50 may include a centrifugal blower 140 connected to a blower inlet 150 and a blower outlet 160. Air from the blower outlet 160 may be directed across the heater core 40. The motor blower further may include a motor 170, which may be connected to an appropriate electric power supply. To provide improved efficiencies in the electric heating system 10, the blower inlet 150 may be spaced a distance D from a side of the tank 20. By way of example, the blower inlet 150 may be a distance D of about ½ inch to about 1½ inches from a side of the tank 20. In one embodiment, the blower inlet 150 may be a distance D of about 1 inch from the side of the tank 20. By locating the blower inlet 150 proximate to the tank 20, the motor blower 50 may intake air that has already been heated, capturing passive heat loss from the tank 20 and, thus, reducing the heat from the heating medium that is needed to provide the desired heat output from the system 10.

Referring again to FIG. 2, a metal strap 190 may be coupled to the tank 20 and the motor blower 50, in accordance with embodiments of the present invention. By way of example, the metal strap 190 may be welded to the top of the tank 20 and also coupled to the motor blower 50. The metal strap 190 may be bent, for example, to form an elbow that is attached to the motor blower 50. The metal strap 190 may function to stabilize the motor blower 50. In addition, the metal strap 190 may also transfer heat from the tank 20 to the motor blower 50, increasing the heat output from the motor blower 50. Capturing passive heat loss from the tank 20 with the metal strap 190 generally should reduce the heat from the heating medium that is needed to provide the desired heat output from the system 10.

The motor blower 50 may be controlled by blower thermostat 180, in accordance with embodiments of the present invention. The blower thermostat 180 may include, for example, a temperature sensor (not illustrated) for sensing the room temperature. The blower thermostat 180 may be set to turn on the motor blower 50 and, thus, the motor 170 at a specified temperature. Any of a variety of different motor blowers may be used in accordance with embodiments of the preset invention. An example of a suitable motor blower is Dayton High Temperature Blower 1TDV4, available from W. W. Grainger, Inc.

As previously mentioned, the electric heating system 10 may be enclosed by cover 60, such as a metal cover. In certain embodiments, the cover 60 may be an enclosure having four sides, a base, and a top. The cover 60 may be sized for enclosing the system 10. In certain embodiments, the cover 60 may be have a width of about 22 inches, a length of about 22 inches, and a height of about 16 inches. Optionally, wheels (e.g., 4 wheels) may be attached to the bottom of the cover 60, providing added mobility to the system 10. The cover 60 may include several openings as desired for particular applications. For example, the cover 60 may include an opening (e.g., a square opening) sized for the heater core 40. By way of further example, the cover 60 may include an opening (e.g, a circular opening) sized for the motor-blower 50. The opening for the motor blower 50 may be provided to prevent and/or reduce overheating of the motor blower 50. By way of further example, there may also be an additional small vent opening in the cover 60 at the back of the motor blower 50.

A variety of suitable wiring configurations may be used for connecting the pump 30, the motor blower 50, the heating element 100, the thermostat 120, and the blower thermostat 180 to an electric power supply. Provided herein is a description of an example wiring configuration that may be used in accordance with one embodiment of the present technique. It should be understood that other suitable wiring configurations may also be used in accordance with embodiments of the present invention. The electric heating system 10 may be placed on a dedicated circuit with a separate breaker, for example, a 20-amp breaker. This circuit may be similar, for example, to a dedicated circuit that may be used for a residential washing machine. There may be a common on/off switch to control the supply of power to the system 10. The pump 30, the thermostat 120, and the blower thermostat 180 may each be separately wired to the power supply. The heating element 100 may be wired to the motor blower 50 with the motor blower 50 wired to the blower thermostat 180. In this manner, the blower thermostat 180 may help to control the temperature of the heating medium. In other words, the blower thermostat 180 may be set to turn on the motor blower 50 when the room temperature reaches a preset temperature. For example, if the blower thermostat 180 is set at 65° F., the motor blower 50 and, thus, the heating element 100 may turn on if the room is at a temperature of 65° F. or less. The pump 30 may also be wired to the motor blow 50, in certain embodiments of the present invention. The thermostat 120 may be separately wired to the electrical outlet.

As previously mentioned, embodiments of the electric heating system 10 of the present invention may be used for central heating and/or space heating. In central heating embodiments, the heater core 40 may be connected to a duct. By way of example, the heater core 40 may be connected in the duct of an HVAC system. FIG. 5 illustrates connection of the heater core 40 in a duct 200, in accordance with one embodiment of the present invention. Heating medium feed 70 may provide the heating medium to the heater core 40 in the duct 200.

The heating medium may be returned to the tank 20 by heating return 80. Air may be forced across the heater core 40 by the motor blower 50. More particularly, air from the blower outlet 160 may be directed across the heater core 40 in the duct 200. Heat may be transferred from the heating medium in the heater core 40 to the air from the blower outlet 160. Duct 200 may then distribute the heated air passing across the heater core 40, as needed for a particular application. For example, the duct 200 may be incorporated into an HVAC system, distributing the heated air throughout a building.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims. While systems and methods are described in terms of “comprising,” “containing,” “having,” or “including” various components or steps, the systems and methods can also “consist essentially of” or “consist of” the various components and steps. 

1. An electric heating system comprising: a tank for storing a heating medium; an electric heating element disposed in the tank for heating the heating medium in the tank; a pump for circulating the heating medium in the electric heating system; a heater core in fluid connection with the tank for exchanging heat between the heating medium and air; and a motor blower for forcing the air across the heater core.
 2. The electric heating system of claim 1, wherein the heating medium is present in the tank, and wherein the heating medium comprises antifreeze.
 3. The electric heating system of claim 1, wherein the tank is not insulated.
 4. The electric heating system of claim 1, wherein the tank is constructed from a material comprising black iron.
 5. The electric heating system of claim 1, wherein the tank is a horizontal rectangular tank.
 6. The electric heating system of claim 1, wherein the heater core is a plate-fin heat exchanger.
 7. The electric heating system of claim 1, wherein the air intake for the motor blower is located a distance of about ½ inch to about 1 inch from a side of the tank for capturing passive heat loss from the tank.
 8. The electric heating system of claim 1, wherein the motor blower is configured to force the air across the heater core for heating a room in which the electric heating system is located.
 9. The electric heating system of claim 1 wherein the motor blower is configured to force the air across the heater core and into a duct system of a heating, ventilation, and air conditioning system of a building.
 10. The electric heating system of claim 1, further comprising a relief valve disposed in a top of the tank.
 11. The electric heating system of claim 1, further comprising a thermostat for controlling the electric heating element and a blower thermostat for controlling the motor blower, wherein the electric heating element is wired to the motor blower.
 12. The electric heating system of claim 1, further comprising a metal strap connecting the tank and the motor blower for capturing passive heat loss from the tank.
 13. The electric heating system of claim 1, further comprising a cover enclosing the electric heating system, the cover comprising at least one opening.
 14. An electric heating system comprising: an un-insulated rectangular tank that comprises a heating medium and that is constructed from a material comprising black iron; wherein the heating medium comprises antifreeze; an electric heating element disposed in the tank for heating the heating medium in the tank; a circulating pump for circulating the heating medium in the electric heating system; a heater core in fluid connection with the tank for exchanging heat between the heating medium and air; a motor blower for forcing the air across the heater core and having an air intake; and wherein the air intake for the motor blower is located a distance of about ½ inch to about 1 inch from a side of the tank.
 15. The electric heating system of claim 14, further comprising a thermostat for controlling the electric heating element and a blower thermostat for controlling the motor blower, wherein the electric heating element is wired to the motor blower.
 16. The electric heating system of claim 14, further comprising a metal strap connecting the motor blower and the tank for capturing passive heat loss from the tank.
 17. A heating method comprising: heating a liquid in a tank with an electric heating element; directing the liquid from the tank to a heater core; forcing air across the heater core with a motor blower, whereby heat is exchanged from the liquid to the air; and returning the liquid from the heater core to the tank.
 18. The method of claim 17 further comprising distributing the heated air through a building by way of a duct.
 19. The method of claim 17 further comprising capturing passive heat from the tank in a metal strap coupled to the tank and the motor blower.
 20. The method of claim 17 further comprising capturing passive heat from the tank in intake air for the motor blower. 